D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082
Needs a `mock` kwarg to Interpreter to not do any parsing of build
files, but only setup the builtins and functions.
Also consolidate the documentation and data tests into one class.
The syntax file does syntax highlighting for numbers, string literals,
comments, etc. Also maintains a list of valid function names.
The plugin does auto-indentation for Meson with two spaces by default.
TODO: explicit errors for decimal numbers (right now, it's just
unhighlighted), check kwargs, default options, etc.